# `Git.Commands.CheckAttr`
[🔗](https://github.com/joshrotenberg/git_wrapper_ex/blob/main/lib/git/commands/check_attr.ex#L1)

Implements the `Git.Command` behaviour for `git check-attr`.

Reports the gitattributes that apply to given paths. This is the
attributes analogue of `Git.Commands.CheckIgnore`.

Pass explicit attribute names in `:attrs`, or set `:all` to report every
attribute that is set on each path. `:cached` reads `.gitattributes` from
the index instead of the working tree.

Output is always requested with `-z` (NUL-delimited records) so paths and
values containing spaces or newlines parse unambiguously.

Stdin mode (`--stdin`) is intentionally not supported because it requires
stdin piping which cannot be driven programmatically via `System.cmd/3`.

# `attribute`

```elixir
@type attribute() :: %{path: String.t(), attr: String.t(), value: String.t()}
```

# `t`

```elixir
@type t() :: %Git.Commands.CheckAttr{
  all: boolean(),
  attrs: [String.t()],
  cached: boolean(),
  paths: [String.t()]
}
```

# `args`

```elixir
@spec args(t()) :: [String.t()]
```

Returns the argument list for `git check-attr`.

Attributes and paths are separated with `--` so paths are never mistaken
for attribute names.

## Examples

    iex> Git.Commands.CheckAttr.args(%Git.Commands.CheckAttr{attrs: ["diff"], paths: ["foo.ex"]})
    ["check-attr", "-z", "diff", "--", "foo.ex"]

    iex> Git.Commands.CheckAttr.args(%Git.Commands.CheckAttr{attrs: ["diff", "text"], paths: ["foo.ex", "bar.png"]})
    ["check-attr", "-z", "diff", "text", "--", "foo.ex", "bar.png"]

    iex> Git.Commands.CheckAttr.args(%Git.Commands.CheckAttr{all: true, paths: ["foo.ex"]})
    ["check-attr", "-z", "-a", "--", "foo.ex"]

    iex> Git.Commands.CheckAttr.args(%Git.Commands.CheckAttr{attrs: ["diff"], paths: ["foo.ex"], cached: true})
    ["check-attr", "-z", "--cached", "diff", "--", "foo.ex"]

# `parse_output`

```elixir
@spec parse_output(String.t(), non_neg_integer()) ::
  {:ok, [attribute()]} | {:error, {String.t(), non_neg_integer()}}
```

Parses the `-z` output of `git check-attr`.

Returns `{:ok, [record]}` where each record is a map with `:path`, `:attr`,
and `:value` keys. `:value` is the raw info string reported by git: one of
`"set"`, `"unset"`, `"unspecified"`, or a custom attribute value.

Empty output (for example `--all` on a path with no attributes) returns
`{:ok, []}`. A non-zero exit code is a real error (unknown option, no
attribute specified, and so on) and returns `{:error, {stdout, exit_code}}`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*